Refining of petroleum oils



Patented Apr. 12, 1932 UNITED STATES PATENT OFFICE JACQUE C. MOBRELL, OF CHICAGO, ILLINOIS, ASSIGNOR TO UNIVERSAL OIL PRODUCTS COMPANY, OF CHICAGO,

ILLINOIS, A CORPORATION SOUTH DAKOTA REFINING OF PETROLEUM OILS No Drawing. Original application filed December 9, 1925, Serial'No. 74,395. Divided and this application flled November 28, 1927. Serial No. 236,377.

This invention relates to improvements in the refining of petroleum oils, and refers more particularly to the subjection of the lighter gravity liquid products produced in petroleum distillation and cracking to the action of various refining agentsfor the purpose of removing or converting ob ectionable color-forming, odor-forming, sulphur and analogous objectionable compounds.

This application is a division of a former application Serial No. 74,395 filed December 9th, 1925.

The essence of the present invention resides in the utilization, as a refining agent, of substantially sulphur-free inorganic or organic acids, or a combination of organic and inorganic acids as the sole refining agent, or in combination with any other suitable refining agent or any combination of refining agents to accomplish the purpose above set forth.

I have discovered thatwhen the lighter gravity liquid products produced in petroleum distillation and cracking are subjected to the action of concentrated sulphuric acid, for the purpose of refining and removing 0bjectionable compounds, the strength of the concentrated acid produces an objectionable reaction, namely, the oxidation of compounds present, particularly in cracked d stillates, reacting in such manner as to leave in the refined oil substances which bring about an unstable condition in the oil with respect to color and odor.

To overcome this objection, various experiments were carried out, and I have discovered that it is possible to substitute for the concentrated sulphuric acid substantially sulphur-free inorganic or organic acids, either alone or in combination. Further, it is possible to overcome the objections pointed out by preceding the treatment with concen-' trated sulphuric acid with the step of subj ecting the oil to the action of the substantially sulphur-free acids above set forth.

It may be pointed out that it is the essence of the present invention to use, essentially as a refining agent, the substantially sulphurfree organic or inorganic acids herein set out, in combination with concentrated sulphuric scribed and then to the sulphuric acid treatment.

The invention contemplates the use of these refining agents, either of themselves or as separate steps, in a method of refining the oil, in combination with other treating agents including plumbite (litharge dissolved in an alkaline solution such as sodium hydroxide, potassium hydroxide, and others), caustic soda, and other alkalies, earthy adsorbent agents, copper salts and the like.

By the term substantially sulphur-free acids as used in the specification and claims, I mean an acid which contains no sulphur in its molecular composition. This term does not refer to the presence of small or accidental amounts of sulphur present'in the materials from which the acid was made or introduced during the course of commercial manufacture, in other words, it does not refer to impurities which contain sulphur.

Among some of the inorganic acids contemplated for use in the present invention may be listed nitric acid, hydrochloric acid, orthophosphoric acid, pyrophosphoric acid and metaphosphoric acid. These inorganic acids pointed out may be used alone or may be mixed with each other. For instance, one

mixture of inorganic acids which has been found suitable for the purpose comprises a small proportion of nitric acid in one of the phosphoric acids.

-Among the organic acids contemplated by the present invention may be listed the following: Acetic (preferably glacial), chlor--' ly where the glacial acetic acid is used, for

the reason that this acid is soluble in the oil and requires a larger proportion of phosphoric acid to reduce this solubility. This points out that the properties of these acids must be considered in their use. Another suitable mixture is the introduction of a small percentage of nitric acid, for example 5 to 10% with phosphoric acid or with acetic acid. The percentage of nitric acid, while not limited to the amount shown, must be kept as a smaller percentage relatively to the other acid in order to cut down its oxidizing properties, and thus obtain the benefits of the mixed acids.

The present invention contemplates more particularly the refining of what are known as cracked distillates, and more particularly those cracked overhead products of end boiling point commercially satisfactory to the trade which are produced directly from the cracking process.

I claim as my invention:

1. Steps in the process of refining a lighter gravity liquid product produced from the cracking of petroleum oil, comprising subjecting the oil first to the action of phosphoric acid, and then to the action of concentrated sulphuric acid, to remove or convert objectionable com ,ounds present in said lighter gravity liqui product.

2. Steps in the process of refining petroleum oil, comprising subjecting the oil first to the action of phosphoricacid, and then to the action of concentrated sulphuric acid, to remove or convert objectionable compounds present in said petroleum oil.

In testimony whereof I afiix my signature.

JACQUE o. MORRELL. 

